Description of On Board Diagnostics
Airbag System (With And Without Side Airbag) On Board Diagnostic (OBD)
General Information
Vehicles From 1999: from VIN 8D XA 200 001
Airbag system includes: side airbag, passenger- side airbag, two front seat belt tensioners, two front side airbags, two or three rear seat belt tensioners and side curtain airbags. In a crash situation, these are ignited centrally by the airbag control module -J234- when specified triggering criteria are met.
In a crash situation, the control module sends a crash signal to the central locking control module. This function is a passive safety feature. It releases door locks and the rear lid lock via the central locking system if an airbag and/or belt tensioner is triggered. Also, inside door lock switches are blocked and interior lighting is switched on. The "crash signal" can be checked using output Diagnostic Test Mode (DTM). Output Diagnostic Test Mode (DTM) (Function 03)
When the airbags and/or belt tensioners are deployed, the control module will record the DTC "Crash data stored."
Airbag control module -J234- must be replaced following:
- The 1st driver-side/passenger-side airbag deployment.
- The 3rd time front seat belt tensioners and/or side airbags are triggered.
For vehicles with airbag 8 (> 10/98) the crash signal cannot be erased using the VAG1551 scan tool after the 3rd deployment.
All vehicles
The control module detects malfunctions and errors in the airbag system and stores them in permanent memory.
After the ignition is switched on, the airbag Malfunction Indicator Lamp (MIL) -K75- lights for about 4 seconds and then goes out.
- If the airbag Malfunction Indicator Lamp (MIL) -K75- does not go out after approximately 4 seconds, the voltage supply for the airbag control module -J234- is not OK. Check DTC memory.
- If the airbag Malfunction Indicator Lamp (MIL) -K75- goes out after 4 seconds and then lights again, either the control module is not coded, an incorrect control module has been installed or a malfunction is present. Check DTC memory.
CAUTION!
- Wiring must only be checked visually!
- Do not perform an electrical continuity check or circuit analysis!
- Check wire routing only when ignition is switched off!
On Board Diagnostic (OBD) functions
The following functions are possible:
01 - Check Control Module Versions
02 - Check DTC Memory
03 - Output Diagnostic Test Mode (vehicles 1997 > 1998 only) (vehicles 1999 > only)
05 - Erase DTC Memory
06 - End Output
07 - Code Control Module
08 - Read Measuring Value Block
NOTE: Function 03 is only available for vehicles 1997 >.